y=3x is linear
y=4x-1 is linear
y=[tex]x^{2}[/tex]+1 is nonlinear
y=0.75x+2 is linear
y=0.5[tex]x^{3}[/tex] in nonlinear
Rule of thumb: If it has exponents, it is nonlinear. If your equation has no exponents, it is linear.
